A sniper rifle similar to the one stolen from an Andover vehicle. Credit: FBI Boston

A 16-year-old boy was arrested Friday on charges he stole two high-powered rifles from an unmarked FBI vehicle, police said.

The weapons were turned in to Lawrence police overnight, two days after they were taken from a vehicle used by a Special Weapons And Tactics (SWAT) unit that had been parked outside an agent's home in Andover.

"The guns have been returned and an arrest has been made," an Andover police official, who asked not to be identified, told Reuters. He declined to provide further details, but CBS Boston reported that fingerprints were used to track down the teenager, who surrendered to police.

The teen is scheduled to be arraigned Friday in Lawrence Juvenile Court, charged with larceny and breaking and entering.

The FBI offered a $20,000 as a reward to anyone who located the rifles, a Colt M16-A1 and an HS Precision Pro-Series 2000 sniper rifle. Andover Police told CBS Boston the reward would be paid, but did not specify who would receive it.

An internal FBI investigation is also underway into whether the weapons were properly stored in the vehicle by the agent.

On Wednesday, an FBI tactical vest was stolen from the Dodge Caravan of an agent in the South End. According to police, there is no indication that the two thefts are related.